Light emitting diode having an adhesive layer and a reflective layer and manufacturing method thereof

ABSTRACT

A light emitting diode having an adhesive layer and a reflective layer and a manufacturing method thereof featured by adhering together a light emitting diode stack and a substrate having a reflective metal layer by use of a transparent adhesive layer so that the light rays directed to the reflective metal layer can be reflected therefrom to improve the brightness of the light emitting diode.

BACKGROUND OF INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a light emitting diode and themanufacturing method thereof. More particularly, the invention isdirected to a light emitting diode having an adhesive layer and areflective layer and the manufacturing method thereof.

[0003] 2. Description of the Prior Art

[0004] Light emitting diodes can be used in a wide variety of devices,for example, optical displays, traffic lights, data storage devices,communication devices, illumination devices, and medical devices. Tomanufacture a light emitting diode of higher brightness is an importanttask of engineers.

[0005] A prior art method for improving LED brightness involves bondingtwo semiconductor parts together by van der Waals forces. However, ithas a disadvantage in that van der Waals forces are too weak to providea sufficient mechanical bonding strength between the two parts andtherefore they are apt to separate.

[0006] In U.S. Pat. No. 5,376,580, a method for bonding an LED stack anda transparent substrate to create an ohmic interface therebetween isdisclosed. The transparent substrate can be made of GaP. The lightgenerated from the LED stack can pass through the LED stack as well asthe transparent substrate. However, this prior art method has to becarried out at about 1000° C. by exerting a coaxial compressive force onthe LED stack and the transparent substrate to form an ohmic interfacetherebetween. The primary disadvantage of this prior art method lies inthat the property of the LED is destroyed by the high temperature duringthe manufacturing process and this results in an LED of low lightemitting efficiency. In addition, the transparent GaP substrate has acolor and a transparency of only about 60 70%. It therefore reducesbrightness of the LED.

[0007] Another prior art method for improving LED brightness involves abonding technique using a metal layer to bond an LED stack and asubstrate. The metal layer forms a bonding layer and a mirror throughits metallic property. Thereby, the light rays emitted from the LEDstack can be reflected at the metal layer and re-enter the LED stackwithout passing through the metal layer and entering the substrate. Thedisadvantage that the some light rays are absorbed by a substrate cantherefore be avoided. In such a manufacturing process, the bondingtemperature of the metal layer is only about 300-450° C. The LEDproperty will not be destroyed at these low temperatures. However, thisbonding technique involves a few disadvantages. One of the disadvantageslies in that although a low bonding temperature will not cause anyreaction between the metal layer and any of the two semiconductor layersto be bonded and therefore a highly reflective metal surface(reflectivity over 90%) and improved light emitting efficiency can beobtained, the bonding effect is not sufficient due to that there is noreaction between the metal layer and any of the semiconductor layers tobe bonded, and an ohmic interface cannot be formed between the metallayer and any of the semiconductor layers to be bonded. Nevertheless, incase that a higher bonding temperature is adopted, the bonding betweenthe metal layer and any of the two semiconductor layers to be bonded isgood. However, the reflectivity of the reflective metal layer will begreatly reduced and therefore the metal layer cannot provide a goodmirror function. This is another disadvantage of the bonding technique.

[0008] To avoid the aforementioned disadvantages, the inventors of thepresent application got an inventive concept to be explained in thefollowing. In case a transparent adhesive layer is used for adhering ametal layer, as mentioned above, to an LED stack, light rays generatedby the LED stack may pass through the transparent adhesive layer, bereflected by the metal layer, and then pass through the LED stack.However, if the metal layer is simply adhered to the LED stack by use ofan adhesive layer, the adhesion between them is achieved only by van derWaals forces and peeling is apt to occur at the adhesion interface. Theinventive concept lies in that a reaction layer is formed between thetransparent adhesive layer and any of the LED stack and the metal layer,wherein a reaction occurs between the reaction layer and the transparentadhesive layer so that hydrogen bonds or ionic bonds are formed toenhance the bonding forces provided by the transparent adhesive layer.Thereby, the transparent adhesive layer can provide an enhancedmechanical strength and thus the above-mentioned disadvantage of peelingcan be avoided. In addition, using the transparent adhesive layer canavoid the above-mentioned disadvantage caused by the bonding between themetal layer and the LED stack. Moreover, a transparent conductive layercan be formed between the transparent adhesive layer and the LED stackfor improving the efficiency of current spreading and thereby canenhance the brightness of the LED.

SUMMARY OF INVENTION

[0009] An object of the invention is to provide a light emitting diodehaving an adhesive layer and a reflective layer and the manufacturingmethod thereof. In the manufacturing method, a transparent adhesivelayer is used to bond an LED stack and a substrate having a reflectivelayer so that light can pass through the transparent adhesive layer andreflected at the reflective layer. On each of the upper and lowersurfaces of the transparent adhesive layer is formed a reaction layer.The reaction layer creates reaction when it and the transparent adhesivelayer is pressurized and heated to enhance the bonding forces at theadhesive surface for improving mechanical strength. The light directedto the reflective layer is reflected out to increase the brightness ofthe light emitting diode. Additionally, the reflective layer can also beformed between the LED stack and the reaction layer so that the adhesivelayer does not have to be limited to a transparent adhesive layer andlight directed to the reflective layer can be reflected out even anon-transparent adhesive layer is used. This method does not have anyproblems relating the decrease in reflectivity and decrease in bondingeffect. Thereby, an effect of total reflection can be obtained and theobject of increasing the brightness of an LED can be achieved.

[0010] A light emitting diode having an adhesive layer and a reflectivelayer in accordance with a preferred embodiment of the inventioncomprises a second substrate, a reflective metal layer formed on thesecond substrate, a first reaction layer formed on the reflective metallayer, a transparent adhesive layer formed on the first reaction layer,a second reaction layer formed on the transparent adhesive layer, atransparent conductive layer formed on the second reaction layer,wherein the upper surface of the transparent conductive layer consistsof a first surface area and a second surface area. A first contact layeris formed on the first surface area. A first cladding layer is formed onthe first contact layer. An active layer is formed on the first claddinglayer. A second cladding layer is formed on the active layer. A secondcontact layer is formed on the second cladding layer. A first electrodeis formed on the second contact layer. A second electrode is formed onthe second surface area.

[0011] The manufacturing method of a light emitting diode in accordancewith a preferred embodiment of the invention comprises the followingsteps: forming in sequence, on a first substrate, a second contactlayer, a second cladding layer, an active layer, a first cladding layer,a first contact layer, a transparent conductive layer, a second reactionlayer to constitute a first stack; forming a reflective metal layer on asecond substrate and forming a first reaction layer on the reflectivemetal layer to constitute a second stack; providing a transparentadhesive layer and using the transparent adhesive layer to bind togetherthe first stack and the second stack by adhering it to the surface ofthe second reaction layer and the surface of the first reaction layer toconstitute a third stack; removing the first substrate to constitute afourth stack; suitably etching the fourth stack to the transparentconductive layer to form an exposed surface area of the transparentconductive layer; and forming a first electrode on the second contactlayer and a second electrode on the exposed surface area of thetransparent conductive layer.

BRIEF DESCRIPTION OF DRAWINGS

[0012]FIG. 1 is a schematic diagram showing a light emitting diodehaving an adhesive layer and a reflective layer in accordance with apreferred embodiment of the invention.

[0013]FIG. 2 is a schematic diagram showing a first stack for use in amethod for manufacturing a light emitting diode having an adhesive layerand a reflective layer, as shown in FIG. 1, in accordance with theinvention.

[0014]FIG. 3 is a schematic diagram showing a second stack for use in amethod for manufacturing a light emitting diode having an adhesive layerand a reflective layer, as shown in FIG. 1, in accordance with theinvention.

[0015]FIG. 4 is a schematic diagram showing a third stack formed, afteradhesive binding the first stack and the second stack and beforeremoving the first substrate, in a method for manufacturing a lightemitting diode having an adhesive layer and a reflective layer, as shownin FIG. 1, in accordance with the invention.

[0016]FIG. 5 is a schematic diagram showing a fourth stack formed, afterremoving the first substrate, in a method for manufacturing a lightemitting diode having an adhesive layer and a reflective layer, as shownin FIG. 1, in accordance with the invention.

[0017]FIG. 6 is a schematic diagram showing a light emitting diodehaving an adhesive layer and a reflective layer in accordance withanother preferred embodiment of the invention.

[0018]FIG. 7 is a schematic diagram showing a light emitting diodehaving an adhesive layer and a reflective layer in accordance with yetanother preferred embodiment of the invention.

[0019]FIG. 8 is a schematic diagram showing a fifth stack for use in amethod for manufacturing a light emitting diode having an adhesive layerand a reflective layer, as shown in FIG. 7, in accordance with theinvention.

[0020]FIG. 9 is a schematic diagram showing a sixth stack for use in amethod for manufacturing a light emitting diode having an adhesive layerand a reflective layer, as shown in FIG. 7, in accordance with theinvention.

[0021]FIG. 10 is a schematic diagram showing a seventh stack formed,after adhesive binding the first stack and the second stack and beforeremoving the first substrate, in a method for manufacturing a lightemitting diode having an adhesive layer and a reflective layer, as shownin FIG. 7, in accordance with the invention.

[0022]FIG. 11 is a schematic diagram showing a light emitting diodehaving an adhesive layer and a reflective layer in accordance with stillyet another preferred embodiment of the invention.

[0023]FIG. 12 is a schematic diagram showing a eighth stack for use in amethod for manufacturing a light emitting diode having an adhesive layerand a reflective layer, as shown in FIG. 11, in accordance with theinvention.

[0024]FIG. 13 is a schematic diagram showing a ninth stack for use in amethod for manufacturing a light emitting diode having an adhesive layerand a reflective layer, as shown in FIG. 11, in accordance with theinvention.

[0025]FIG. 14 is a schematic diagram showing a tenth stack formed, afteradhesive binding the first stack and the second stack and beforeremoving the first substrate, in a method for manufacturing a lightemitting diode having an adhesive layer and a reflective layer, as shownin FIG. 11, in accordance with the invention.

DETAILED DESCRIPTION

[0026] Referring to FIG. 1, a light emitting diode having an adhesivelayer and a reflective layer 1 in accordance with a preferred embodimentof the invention comprises a second substrate 10, a reflective metallayer 11 formed on the second substrate 10, a first reaction layer 22formed on the reflective metal layer 11, a transparent adhesive layer 12formed on the first reaction layer 22, a second reaction layer 23 formedon the transparent adhesive layer 12, a transparent conductive layer 21formed on the second reaction layer 23, wherein the upper surface of thetransparent conductive layer 21 consists of a first surface area and asecond surface area. A first contact layer 13 is formed on the firstsurface area. A first cladding layer 14 is formed on the first contactlayer 13. An active layer 15 is formed on the first cladding layer 14. Asecond cladding layer 16 is formed on the active layer 15. A secondcontact layer 17 is formed on the second cladding layer 16. A firstelectrode 19 is formed on the second contact layer 17. A secondelectrode 20 is formed on the second surface area.

[0027] Referring to FIGS. 1 to 5, the manufacturing method of the lightemitting diode 1 comprises the following steps: forming in sequence, ona first substrate 18, a second contact layer 17, a second cladding layer16, an active layer 15, a first cladding layer 14, a first contact layer13, a transparent conductive layer 21, a second reaction layer 23 toconstitute a first stack 2; forming a reflective metal layer 11 on asecond substrate 10 and forming a first reaction layer 22 on thereflective metal layer 11 to constitute a second stack 3, as shown inFIG. 3; providing a transparent adhesive layer 12 and using thetransparent adhesive layer 12 to bind together the first stack 2 and thesecond stack 3 by adhering it to the surface of the second reactionlayer 23 and the surface of the first reaction layer 22 to constitute athird stack 4, as shown in FIG. 4; removing the first substrate 18 toconstitute a fourth stack 5, as shown in FIG. 5; suitably etching thefourth stack 5 to the transparent conductive layer 21 to form an exposedsurface area of the transparent conductive layer 21; and forming a firstelectrode 19 on the second contact layer 17 and a second electrode 20 onthe exposed surface area of the transparent conductive layer 21.

[0028] A light emitting diode having an adhesive layer and a reflectivelayer 6 in accordance with another preferred embodiment of the inventionis shown in FIG. 6. The LED structure and manufacturing method of thisLED 6 is similar to that in accordance with the aforementioned preferredembodiment except that the reflective metal layer 11 is replaced by areflective oxide layer 611 by which the light directed to the reflectiveoxide layer 611 can be reflected and taken out.

[0029] Referring to FIG. 7, a light emitting diode having an adhesivelayer and a reflective layer 7 in accordance with yet another preferredembodiment of the invention comprises a reflective metal substrate 710;a first reaction layer 722 formed on the reflective metal substrate 710;a transparent adhesive layer 712 formed on the first reaction layer 722;a second reaction layer 723 formed on the transparent adhesive layer712; a transparent conductive layer 721 formed on the second reactionlayer 723; wherein the transparent conductive layer 721 comprises afirst surface area and a second surface area; a first contact layer 713formed on the first surface area; a first cladding layer 714 formed onthe first contact layer 713; an active layer 715 formed on the firstcladding layer 714; a second cladding layer 716 formed on the activelayer 715; a second contact layer 717 formed on the second claddinglayer 716; a first electrode 719 formed on the second contact layer 717;and the second electrode 720 formed on the second surface area.

[0030] Referring to FIGS. 7 to 10, the manufacturing method of the LED 7comprises the following steps: forming in sequence, on a first substrate718, a second contact layer 717, a second cladding layer 716, an activelayer 715, a first cladding layer 714, a first contact layer 713, atransparent conductive layer 721, a second reaction layer 723 toconstitute a fifth stack 8; forming a first reaction layer 722 on areflective metal substrate 710 to constitute a sixth stack 9; bondingthe surface of the second reaction layer of the first stack with thesurface of the first reaction layer of the sixth stack by use of atransparent adhesive layer 712; removing the first substrate 718 toleave a seventh stack 100; suitably etching the seventh stack 100 toform an exposed surface area of the transparent conductive layer 721;and forming a first electrode 719 and a second electrode 720respectively on the second contact layer 717 and the exposed surfacearea of the transparent conductive layer 721.

[0031] Referring to FIG. 11, a light emitting diode 110 in accordancewith another preferred embodiment of the invention comprises a secondsubstrate 1110; a first reaction layer 1122 formed on the secondsubstrate 1110; an adhesive layer 1112 formed on the first reactionlayer 1122; a second reaction layer 1123 formed on the adhesive layer1112; a reflective metal layer 1111 formed on the second reaction layer1123; a transparent conductive layer 1121 formed on the reflective metallayer 1111, wherein the transparent conductive layer 1121 comprises afirst surface area and a second surface area; a first contact layer 1113formed on the first surface area; a first cladding layer 1114 formed onthe first contact layer 1113; an active layer 1115 formed on the firstcladding layer 1114; a second cladding layer 1116 formed on the activelayer 1115; a second contact layer 1117 formed on the second claddinglayer 1116; a first electrode 1119 formed on the second contact layer1117; and a second electrode 1120 formed on the second surface area.

[0032] Referring to FIGS. 12 to 14, a method for manufacturing the lightemitting diode 110 comprises the following steps: forming, in sequence,on a first substrate 1118, a second contact layer 1117, a secondcladding layer 1116, an active layer 1115, a first cladding layer 1114,a first contact layer 1113, a transparent conductive layer 1121, areflective metal layer 1111, a second reaction layer 1123 to constitutean eighth stack 120; forming a first reaction layer 1122 on a secondsubstrate 1110 to constitute a ninth stack 130; bonding together thesurface of the second reaction layer 1123 of the eighth stack 120 andthe surface of the first reaction layer 1122 of the ninth stack 130 byuse of a adhesive layer 1112; removing the first substrate 1118 toconstitute a tenth stack 140; suitably etching the tenth stack 140 tothe transparent conductive layer 1121 to form an exposed surface area ofthe first contact layer 1113; and forming a first electrode 1119 and asecond electrode 1120 respectively on the second contact layer 1117 andthe exposed surface area of the first contact layer 1113.

[0033] The first substrate 18, 718, or 1118 comprises at least amaterial selected from the group consisting of GaP, GaAs, and Ge. Thesecond substrate 10 or 1110 comprises at least a material selected fromthe group consisting of Si, GaAs, SiC, Al2O3, glass, GaP, GaAsP, andAlGaAs. The transparent adhesive layer 12 or 1112 comprises at least amaterial selected from the group consisting of polyimide (PI),benzocyclobutene (BCB), perfluorocyclobutane (PFCB), and the like. Thefirst reaction layer 22, 722, or 1122 comprises at least a materialselected from the group consisting of SiNx, Ti, and Cr.The secondreaction layer 23, 723, or 1123 comprises at least a material selectedfrom the group consisting of SiNx, Ti, and Cr, and the like. Thereflective metal substrate 710 comprises at least a material selectedfrom the group consisting of Sn, Al, Au, Pt, Zn, Ag, Ti, Pb, Pd, Ge, Cu,AuBe, AuGe, Ni, PbSn, AuZn, and the like. The first contact layer 13,713, or 1113 comprises at least a material selected from the groupconsisting of GaP, GaAs, GaAsP, InGaP, AlGaInP, and AlGaAs. Thereflective oxide layer 611 comprises at least a material selected fromthe group consisting of SiNx, SiO₂, Al2O3, TiO2, MgO, and the like. Thereflective metal layer 11 or 1111 comprises at least a material selectedfrom the group consisting of In, Sn, Al, Au, Pt, Zn, Ag, Ti, Pb, Pd, Ge,Cu, AuBe, AuGe, Ni, PbSn, AuZn, and the like. Each of the first claddinglayer 14, 714, or 1114, the active layer 15, 715, or 1115, and thesecond cladding layer 16, 716, or 1116 comprises AlGaInP. The secondcontact layer 17, 717, 1117 comprises at least a material selected fromthe group consisting of GaP, GaAs, GaAsP, InGaP, AlGaInP, and AlGaAs.The transparent conductive layer 21, 721, or 1121 comprises at least amaterial selected from the group consisting of indium tin oxide, cadmiumtin oxide, antimony tin oxide,zinc oxide, and zinc tin oxide.

[0034] Although the preferred embodiments of the invention has beenillustrated and described in the above, it will be obvious to thoseskilled in the art that various modifications may be made withoutdeparting from the scope and spirit of the invention defined by theappended claims.

What is claimed is:
 1. A method for manufacturing a light emitting diodehaving an adhesive layer and a reflective layer, comprising at least thesteps of:forming an LED stack over a first substrate;forming a firstreaction layer over said LED stack;forming a reflective layer over asecond substrate;forming a second reaction layer over said reflectivelayer; and holding together said first reaction layer and said secondreaction layer by means of a transparent adhesive layer.
 2. A method formanufacturing a light emitting diode having an adhesive layer and areflective layer according to claim 1, wherein said reflective layer isa reflective metal layer.
 3. A method for manufacturing a light emittingdiode having an adhesive layer and a reflective layer according to claim2, wherein said reflective metal layer comprises at least a materialselected from the group consisting of In, Sn, Al, Au, Pt, Zn, Ag, Ti,Pb, Pd, Ge, Cu, AuBe, AuGe, Ni, PbSn, AuZn, and the like.
 4. A methodfor manufacturing a light emitting diode having an adhesive layer and areflective layer according to claim 1, wherein said reflective layer isa reflective oxide layer.
 5. A method for manufacturing a light emittingdiode having an adhesive layer and a reflective layer according to claim4, wherein said reflective oxide layer comprises at least a materialselected from the group consisting of SiNx, SiO₂, Al2O3, TiO2, MgO, andthe like.
 6. A method for manufacturing a light emitting diode having anadhesive layer and a reflective layer according to claim 1, wherein saidtransparent adhesive layer comprises at least a material selected fromthe group consisting of polyimide (PI), benzocyclobutene (BCB),perfluorocyclobutane (PFCB), and the like.
 7. A method for manufacturinga light emitting diode having an adhesive layer and a reflective layeraccording to claim 1, wherein said first reaction layer or said secondreaction layer comprises at least a material selected from the groupconsisting of SiNx, Ti, Cr, and the like.
 8. A method for manufacturinga light emitting diode having an adhesive layer and a reflective layeraccording to claim 1, wherein forming a reflective layer over a secondsubstrate comprises the steps of forming a semiconductor stack over saidsecond substrate and forming a reflective layer over said semiconductorstack.
 9. A method for manufacturing a light emitting diode having anadhesive layer and a reflective layer according to claim 1, furthercomprising the step of removing said first substrate.
 10. A method formanufacturing a light emitting diode having an adhesive layer and areflective layer, comprising at least the steps of:forming an LED stackover a first substrate;forming a first reaction layer over said LEDstack;forming a second reaction layer over areflective metal substrate;and holding together said first reaction layer and said second reactionlayer by means of a transparent adhesive layer.
 11. A method formanufacturing a light emitting diode having an adhesive layer and areflective layer according to claim 10, wherein said reflective metalsubstrate comprises at least a material selected from the groupconsisting of Sn, Al, Au, Pt, Zn, Ag, Ti, Pb, Pd, Ge, Cu, AuBe, AuGe,Ni, PbSn, AuZn, and the like.
 12. A method for manufacturing a lightemitting diode having an adhesive layer and a reflective layer accordingto claim 10, wherein said transparent adhesive layer comprises at leasta material selected from the group consisting of polyimide (PI),benzocyclobutene (BCB), perfluorocyclobutane (PFCB), and the like.
 13. Amethod for manufacturing a light emitting diode having an adhesive layerand a reflective layer according to claim 10, wherein said firstreaction layer or said second reaction layer comprises at least amaterial selected from the group consisting of SiNx, Ti, Cr, and thelike.
 14. A method for manufacturing a light emitting diode having anadhesive layer and a reflective layer according to claim 10, wherein thestep of forming a second reaction layer over a reflective metalsubstrate comprises the steps of forming a reflective layer over saidreflective metal substrate and forming a second reaction layer over saidreflective layer.
 15. A method for manufacturing a light emitting diodehaving an adhesive layer and a reflective layer according to claim 10,further comprising the step of removing said first substrate.
 16. Amethod for manufacturing a light emitting diode having an adhesive layerand a reflective layer, comprising at least the steps of:forming an LEDstack over a first substrate;forming a reflective layer over said LEDstack;forming a first reaction layer over said reflective layer;forminga second reaction layer over a second substrate; and holding togethersaid first reaction layer and said second reaction layer by means of anadhesive layer.
 17. A method for manufacturing a light emitting diodehaving an adhesive layer and a reflective layer according to claim 16,wherein said reflective layer is a reflective metal layer.
 18. A methodfor manufacturing a light emitting diode having an adhesive layer and areflective layer according to claim 16, wherein said reflective layer isa reflective oxide layer.
 19. A method for manufacturing a lightemitting diode having an adhesive layer and a reflective layer accordingto claim 17, wherein said reflective metal layer comprises at least amaterial selected from the group consisting of In, Sn, Al, Au, Pt, Zn,Ag, Ti, Pb, Pd, Ge, Cu, AuBe, AuGe, Ni, PbSn, AuZn, and the like.
 20. Amethod for manufacturing a light emitting diode having an adhesive layerand a reflective layer according to claim 18, wherein said reflectiveoxide layer comprises at least a material selected from the groupconsisting of SiNx, SiO₂, Al2O3, TiO2, MgO, and the like.
 21. A methodfor manufacturing a light emitting diode having an adhesive layer and areflective layer according to claim 16, wherein said first reactionlayer or said second reaction layer comprises at least a materialselected from the group consisting of SiNx, Ti, Cr, and the like.
 22. Amethod for manufacturing a light emitting diode having an adhesive layerand a reflective layer according to claim 16, further comprising thestep of removing said first substrate.
 23. A light emitting diode havingan adhesive layer and a reflective layer, comprising at least:asubstrate;a reflective layer formed over the substrate;a first reactionlayer formed over said reflective layer;a transparent adhesive layerformed over said first reaction layer;a second reaction layer formedover said transparent adhesive layer; andan LED stack formed over saidsecond reaction layer.
 24. A light emitting diode having an adhesivelayer and a reflective layer according to claim 23, further comprising atransparent conductive layer between said second reaction layer and saidLED stack.
 25. A light emitting diode having an adhesive layer and areflective layer according to claim 23, wherein said reflective layer isa reflective metal layer.
 26. A light emitting diode having an adhesivelayer and a reflective layer according to claim 23, wherein saidreflective layer is a reflective oxide layer.
 27. A light emitting diodehaving an adhesive layer and a reflective layer according to claim 25,wherein said reflective metal layer comprises at least a materialselected from the group consisting of In, Sn, Al, Au, Pt, Zn, Ag, Ti,Pb, Pd, Ge, Cu, AuBe, AuGe, Ni, PbSn, AuZn, and the like.
 28. A lightemitting diode having an adhesive layer and a reflective layer accordingto claim 26, wherein said reflective oxide layer comprises at least amaterial selected from the group consisting of SiNx, SiO₂, Al2O3, TiO2,MgO, and the like.
 29. A light emitting diode having an adhesive layerand a reflective layer according to claim 23, wherein said transparentadhesive layer comprises at least a material selected from the groupconsisting of polyimide (PI), benzocyclobutene (BCB),perfluorocyclobutane (PFCB), and the like.
 30. A light emitting diodehaving an adhesive layer and a reflective layer according to claim 23,wherein said first reaction layer or said second reaction layercomprises at least a material selected from the group consisting ofSiNx, Ti, Cr, and the like.
 31. A light emitting diode having anadhesive layer and a reflective layer, comprising at least:a substrate;afirst reaction layer formed over the substrate;a adhesive layer formedover said first reaction layer;a second reaction layer formed over saidadhesive layer;a reflective layer formed over said second reactionlayer; andan LED stack formed over said reflective layer.
 32. A lightemitting diode having an adhesive layer and a reflective layer accordingto claim 31, further comprising a transparent conductive layer betweensaid reflective layer and said LED stack.
 33. A light emitting diodehaving an adhesive layer and a reflective layer according to claim 31,wherein said reflective layer is a reflective metal layer.
 34. A lightemitting diode having an adhesive layer and a reflective layer accordingto claim 31, wherein said reflective layer is a reflective oxide layer.35. A light emitting diode having an adhesive layer and a reflectivelayer according to claim 33, wherein said reflective metal layercomprises at least a material selected from the group consisting of In,Sn, Al, Au, Pt, Zn, Ag, Ti, Pb, Pd, Ge, Cu, AuBe, AuGe, Ni, PbSn, AuZn,and the like.
 36. A light emitting diode having an adhesive layer and areflective layer according to claim 34, wherein said reflective oxidelayer comprises at least a material selected from the group consistingof SiNx, SiO₂, Al2O3, TiO2, MgO, and the like.
 37. A light emittingdiode having an adhesive layer and a reflective layer according to claim31, wherein said transparent adhesive layer comprises at least amaterial selected from the group consisting of polyimide (PI),benzocyclobutene (BCB), perfluorocyclobutane (PFCB), and the like.
 38. Alight emitting diode having an adhesive layer and a reflective layeraccording to claim 31, wherein said first reaction layer or said secondreaction layer comprises at least a material selected from the groupconsisting of SiNx, Ti, Cr, and the like.
 39. A light emitting diodehaving an adhesive layer and a reflective layer, comprising at least:areflective metal substrate;a first reaction layer formed over thereflective metal substrate;a transparent adhesive layer formed over saidfirst reaction layer;a second reaction layer formed over saidtransparent adhesive layer; andan LED stack formed over said secondreaction layer.
 40. A light emitting diode having an adhesive layer anda reflective layer according to claim 39, further comprising atransparent conductive layer between said second reaction layer and saidLED stack.
 41. A light emitting diode having an adhesive layer and areflective layer according to claim 39, wherein said reflective metalsubstrate comprises at least a material selected from the groupconsisting of Sn, Al, Au, Pt, Zn, Ag, Ti, Pb, Pd, Ge, Cu, AuBe, AuGe,Ni, PbSn, AuZn, and the like.
 42. A light emitting diode having anadhesive layer and a reflective layer according to claim 39, whereinsaid transparent adhesive layer comprises at least a material selectedfrom the group consisting of polyimide (PI), benzocyclobutene (BCB),perfluorocyclobutane (PFCB), and the like.
 43. A light emitting diodehaving an adhesive layer and a reflective layer according to claim 39,wherein said first reaction layer or said second reaction layercomprises at least a material selected from the group consisting ofSiNx, Ti, Cr, and the like.